Seat system with a backrest

ABSTRACT

A seat system comprising a backrest, a seat, means adapted to pivot said seat about a horizontal axis positioned in a base, means to attach said backrest to the supporting element for said seat by means of a hinged connection, a base, a spring means, said backrest being connected with said base by at least one said spring means, and means to arrange said seat system so that, when a load acts upon said seat system, said means simultaneously produces in a stabilizing manner a forwardly directed compressive force on said backrest being adapted to the user, and a supporting force against the supporting element of said seat.

United States Patent 21 Claims, 14 Drawing Figs.

U.S. Cl 297/304, 297/316 Int. Cl A47c 3/00 Field 0! Search 297/3 I6, 304, 305, 337

[56] Reierences Cited UNITED STATES PATENTS 2,859,799 11/1958 Moore 297/3 l6 Primary Examiner- Reinaldo P. Machado Allorney-Oilo John Munz ABSTRACT: A seat system comprising a backrest, a seat, means adapted to pivot said seat about a horizontal axis posi tioned in a base, means to attach said backrest to the supporting element for said seat by means ofa hinged connection, a base, a spring means, said backrest being connected with said base by at least one said spring means, and means to arrange said seat system so that, when a load acts upon said seat system, said means simultaneously produces in a stabilizing manner a forwardly directed compressive force on said backrest being adapted to the user, and a supporting force against the supporting element of said seat,

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SHIN 3 (If 7 INVENTORS GERDI KERSTHOLT FRITZ KERSTHOLT PATENT ATTORNEY PATENIED M1631 Inn 3.602537 saw u or 7 GERDI KERSTHOLT FRITZ KERSTHOLT die/M M7 PATENT ATTORNEY PATENTEDAUUSIIU'II 3.602.537

sum s or 7 fill/[NW3 GERDI KERSTHOLT FRITZ KERSTHOLT mmvr nr 0015) PATENIHI m3! an SHEEI B [If 7 lM/LWTORS GERDI KERSTHOLT FRITZ KERSTHOLT PATENT ATTORNEY PATENIFIHunaxmn 3.602537 sum 7 or 7 INVENmRS GERDI KERSTHOLT FRITZ KERSTHOLT PATENT ATTORNEY SEAT SYSTEM WITH A BACKREST DESCRIPTION OF THE PRIOR ART Known in the prior art are seat systems in which the backrest is rigidly secured to the supporting element of the seat. This is the case, for example, in the well-known chairs.

The seat is defined as, and also hereinafter understood to be, the geometrical surface which comes into contact with the user; in other words, the surface of the upholstered seat in an armchair, the surface of the seat board in a chair, etc.

Also known in the art are seat systems in which the backrest is variable in its angular position with respect to the seat. When such a seat system is used for an armchair, the backrest is secured by means of hinges to the rear edge of the frame supporting the upholstered seat superstructure. This frame is displaceably positioned in the base. Depending upon the direction of displacement, the backrest adjusts to a flatter or steeper position. Another seat system of this type is the wellknown office chair whose backrest consists of a flat spring with a pivotally mounted wooden backrest. The backrest wood is provided so as to be displaceable in height, and the flat spring, engaging with its lower end to a greater or lesser degree under the seat, may be clamped thereto.

Moreover it is no longer new is seat systems to provide the supporting element for the seat and the backrest as a rigid unit which is secured to a base with the aid of a spring means acting upon the supporting element. By virtue of this means, the user can recline the seat more or less markedly. In so doing, he must brace himself against the floor and exert a certain compressive force during the reclined spatial condition so that the seat remains in that position. The application of this force becomes tiresome after already a relatively short period of time. Very soon the user will therefore return the seat system to the normal position in which the seat is almost horizontal and the application of pressure is no longer necessary. Such seat systems are thus not suited to allow the user a prolonged stay in a position of rest in which the backrest is strongly reclined from its normal position.

The known seat systems further have the disadvantage that they do not adjust automaticallyto the respective sitting position of the user. As a result thereof, the known seat system is not adapted in the best possible manner to the users respective sitting position since, as is well known, the user changes his position while using the seat system. This is found to be uncomfortable, when sitting, in the long run.

BACKGROUND OF THE INVENTION Field Of The Invention The present invention relates to a seat system with a backrest which does not have the disadvantages and drawbacks outlined hereinabove.

SUMMARY OF THE INVENTION Among the objects of the present invention are the following: The seat system proposed by the present invention is intended to adapt automatically to the respective sitting position of the user. Furthermore, a relative position of the seat system which is in conformity with the body of the user and a good support for the back of the user are to be assured at all times. This applies particularly to the three known essential sitting positions, namely the writing position in which the upper part of the body leans forwardly, the upright sitting position, and the rearwardly reclined listening position.

The aforementioned objects are obtained with a set with a backrest, wherein the seat is pivotable about a horizontal axis positioned in a base and wherein the backrest is secured to the supporting element for the seat preferably by means of a hinged connection. The seat system proposed by the present invention is characterized in that the backrest is in operative connection with the base or the floor by way of at least one spring means, this means and the points of application thereof being so chosen that, under a load, this means simultaneously produces in a stabilizing manner a forwardly directed compressive force on said backrest, which force is adapted to the user, and a supporting force against the supporting element of the seat. The novel seat system may also be so constructed that the upper part of the system including the supporting element for the set and the backrest being rigidly secured to the latter is in operative connection with the base or the floor by way of at least one spring means, this means and the points of application thereof being so chosen that, under a load, this means simultaneously produces in a stabilizing manner a forwardly directed compressive force on said backrest, which force is adapted to the user, and a supporting force against the supporting element of the seat. Means may be provided for delimiting the movements of the seat. Means for adjusting the spring tension, or elastic force, to the weight of the user may also be provided. lt is further possible to provide means for locking the seat and/or the back rest in different positions thereof. These means may be butt straps being equipped with apertures. When several of such means are present simultaneously, they may be adapted to be rendered operative and inoperative by means of at least one common handle. Elastic means may be provided which act upon the handle and allow for rendering the locking means inoperative only against the action of a elastic force. The seat may be disposed displaceably in the horizontal direction. A support may be positioned there ahead which is displaceable with regard to height and/or depth of the seat, means being provided for locking the support in variable positions. Moreover, one of the points of application of the spring means may be displaceably positioned.

The advantage of the novel seat system according to the present invention resides in that the user can lie or lean against the backrest at all times and independently of the respective angle of incidence of the seat. it has been found that the user is supported in his respective sitting position independently of whether the seat is inclined forwardly, horizontal, or reclined toward the rear. Damages to the posture of the user, which can occur easily particularly in the case of persons having a sedentary occupation, are thereby effectively eliminated. A sitting only on the front edge of the seat, as it is observed oftentimes in the case of typing personnel, is no longer readily possible since the seat will in that case adjust to its extreme inclined position and additionally become so steep and sloping toward the front that this sitting position is found to be definitely uncomfortable. For the reasons set forth above, the novel seat system is particularly suitable also for children because they will be made to sit properly at all times by virtue of the peculiar construction of the seat system. For school children it is advantageous to provide an attachment or deposit which is laterally secured to the supporting element for the seat and allows for having, for example, a book bag handy at all times, independently of the respective angle of incidence of the seat itself.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed drawings in which like reference numerals designate like of equivalent parts throughout the figures thereof and wherein FIGS. 1 to 10 inclusive depict embodiments and details thereof, which provide a linkage connection for the backrest and the seat support;

FIG. 1 is a cross-sectional view of an embodiment of the invention;

FIGS. 24 and 2b are variations of details of FIG. I;

FIGS. 3, 4 and 5 are cross-sectional views of other variations of details of F IG. 1;

FIG. 6 depicts a principle of the invention common to the above variations as applied to seats in engine-operated vehicles and the like;

FIG. 7 is a cross-sectional view of a variation of a detail of FIG. 1;

FIGS. 80 and 8b depict details of variations of FIG. 1',

FIGS. 9 and 10 are schematic showings of elements of the invention in cross section;

FIGS. 11 and 12 depict details in cross section and in perspective, respectively, which can be incorporated into or substituted for the elements of the previous figures to provide a fixed connection between the seat support and the backrest.

In the seat system illustrated in FIG. 1, the frame 10 serving as supporting element for the seat board or support 10' is pivotally positioned about an axle 11 in a base. This base consists essentially of two U-shaped tubes 12 which are reinforced by means of struts or crossbars l and connected with each other by means of rods 13, 14 and 16. The backrest is secured to the frame by means of a hinged or linkage connection 17. This backrest consists of a frame 18 and of a backrest leaf 19 being secured to the latter by means of a hinge or link 20. The frame 18 includes a crossbar 21. Accommodated between this crossbar 21 and the rod 16 is a telescopic shock absorber means. It consists of the rod-shaped and, respectively, sleeveshaped structural elements 22, 23 which are rotatably positioned at the rods, adapted to be slid into each other and supported against each other by means of a spring 24. The rod 23 is provided, at the lower end thereof, with a thread with which a nut 23' is guided. The latter serves for making it possible to vary the tension of the spring. At the height of the hinged connection 17, a butt strap 25 is rotatably mounted at the frame 10. This strap is guided in an eye 26 which ha been shown in cross section in the drawing and which is secured to the sleeve 22. The butt strap 25 includes apertures 28 as well as two stops 27. The latter delimit the possible movements of the frame 10. The apertures 28 in connection with corresponding apertures in the sleeve 22 as well as the rod 23 allow for locking the seat in a desired position by means of a pin 29 which is inserted into one of these apertures.

The seat system according to the invention operates in such a manner that, when the pin 29 is pulled out, the back of the user is at all times in contact with the backrest independently of the position of the seat or seat support. This applies also when the user has shifted his sitting position on the seat for wardly. When only the front edge of the seat is actually weighted or loaded, the latter will set itself to such a markedly forwardly inclined position that this particular setting feels uncomfortable to the user. He will therefore improve his sitting position by shifting his weight on to the entire seat.

According to a modified embodiment, the seat plate 10' proper can be provided with eyes enclosing the axle 11 and, at the rear edge thereof, with the hinged connection to the backrest so that the frame 10 can be omitted. In this case. the plate 10' itself is the supporting element for the seat support.

FIG. 2a shows the same arrangement of the frame 10, the seat plate 10', the backrest l8 and the spring means 22, 23, 24. 23'. The axle 11, however, is secured in this instance to an upright-type base and the spring means is supported against one of the transverse brackets of this base. In addition thereto, a deposit or attachment 30 which is made of round iron, for example, may be mounted at the frame 10. Since this deposit or attachment is rigidly secured to the frame 10, it will concomitantly execute the movements thereof. As a result, any material placed thereon, such as a book bag for example, has at all times the same position with respect to the user, which the latter will find to be of great help. The perspective detail shown on the left-hand side illustrates the configuration of such a deposit or attachment.

FIG. 2b illustrates the arrangement of the frame 10, the seat plate 10', the back rest 18 an the spring means 22, 23, 24, 23' in connection with an uprighbtype base in which the upper part of the seat system is rotatable and the height of the seat, or seat support. is variable. The axle 11 is secured to a sleeve 74 which is slipped or put over a center support 75 resting upon a cross base. Rigidly mounted at the sleeve 74 is an angular member 76 and the spring means engages at the free-standing angle thereof. During a displacement of the sleeve 74 along the center support 75 with the use of well-known means which have therefore not been further illustrated herein, the coordinated spring tension or elastic force is maintained in the same manner as when the upper portion of the seat system is pivoted about the center support.

FIG. 3 illustrates an embodiment of the novel seat system in which the frame 32 of the backrest projects downwardly beyond the frame 10 and comprises two bends. It is rotatably attached to the frame 10 by means of butt straps 32. The lower end of the frame 32 extends between the base 12, l3, l4 and is supported thereagainst by means of a telescopic shock absorber means 33. In place of this means or in connection therewith, a tension spring 34 may be employed. For purposes of delimiting the movements of the frame 10 and hence of the seat support, a butt strap 35 is rotatably positioned at the frame 10 and encloses with the slot thereof a guide pin 36 being secured to the base. By changing the means 33 and, respectively, the spring 34 to another one of the slots 38, the elastic force acting upon the back rest may be varied. A buffer 37 serves for delimiting the movements of the backrest.

The seat system shown in FIG. 4 also comprises an uprighttype base with the axle 11 being mounted at the upper end thereof. The frame 40 of the backrest is extended here again to under the seat support and guided by means of a slot 40 by a bolt attached to the base. At the lower end thereof, a tension spring 41 engages which is secured to the upright or stand of the base. The movements of the frame 10 are delimited by two ropes 42, 43 being attached to the stand.

FIG. 5 illustrates a seat system in which the backrest is supported at the base by means of a leaf spring 45. The frame 18 of the backrest comprises in proximity to the hinged connection 17 a support 46 which acts as a delimiting means against the frame 10. The spring is provided at the two ends thereof with one eye or lug portion each. One lug portion encloses the rod 13 of the base, the other one encloses the crossbar 21 of the backrest A rod 47 which may be placed into different recesses of the crossbars 48 serves for supporting the spring 45. The action of the spring 45 becomes stronger or weaker depending upon the pair of recesses into which the rod 47 is placed. It may thus be coordinated to the weight of the user. Shoulder portions 47 secure the rod 47 in position in a direction at right angle to the plane of the drawing. The same means as in the embodiment of FIG. 3 are present for delimiting the movements of the frame 10. The adjustment of the elastic force by the different placement of the rod 47 may be complemented in that the seat support of the seat plate 10' is displaceably positioned against the supporting element thereof within the shape of the frame 10, and sliding tubes I0" serve for this purpose. By varying the seat depth, i.e. by dis placing or shifting the seat proper rearwardly or forwardly, the force of the spring may be finely matched to the weight of the user. The respective position of the seat may be fixed by means of a screw, for example. It is understood that the displacement of the seat either forwardly or rearwardly may also be carried out in that the frame 10 is positioned in sliding tubes which are pivotally positioned on the axle [1. In this case the seat board 10' is rigidly secured to the frame 10. Such a position of the frame 10 is schematically illustrated in FIG. 8b.

FIG. 6 illustrates the principle common to all of the embodiments described hereinbefore used for a seat system for motor vehicles. Attached to the frame 50 of the seat, which is in this case the supporting element for the seat support, is the frame 51 of the backrest via a hinged connection 17. The frame 50 is pivotable about an axle 11 being mounted in a box-shaped base 52. A leaf spring 53 supports the back rest. This spring 53 is secured with one end thereof in the base 52. The other end is provided as elongated lug portion and encloses a crossbar 54 in the frame 51. For varying the force of the spring serves a block 56 which is guided in a slide or rail 57 and which may be manually shifted by means of a spindle 55. This block 56 comprises a recess through which the spring 53 extends. The

backrest of a motor vehicle seat should be adapted to be folded forwardly within wide limits. For this reason the spring 53 comprises a joint being locked in the clockwise direction which, in connection with the elongated lug portion at the upper end of the spring, allows for folding the backrest forwardly. The movements of the frame 50 are delimited by the specific configuration of the base. Locking means (not shown) may be provided for retaining the seat system in the adjusted position once it has been chosen.

It should be noted that the relative positions of the backrests shown in FIGS. 20 to 6 presuppose already a loaded or weighted position of the seat system. In he unloaded position thereof, the back rests are positioned more forwardly, as indicated in FIG. 1.

Variations regarding these illustrations are possible. For example, in the place of the one spring means respectively shown, two or more springs may be utilized. The fixing means illustrated have been chosen as examples since they can be represented in a simple manner. This manner of representation does not represent, however, a restriction to the means shown.

It may be advantageous to vary the relative height of the seat against the floor and hence to adapt it to the height of the user. An example for such a seat is illustrated in FIG. 7. The seat shown therein is similar to that of FIG. 1. In this case, however, the axle 11 comprises one rod-shaped downwardly directed projection 80 each being attached at both ends thereof at right angle. These projections are slidingly positioned in guide sleeves 81 which are secured to the base. Different heights of the axle 11 may be adjusted by means of pins 82. In order to be able to adapt the spring means to such a height adjustment, the spring means consisting of telescopically provided rod-shaped and, respectively, sleeve-shaped structural elements 88, 89 as well as of a supporting spring 90 includes at the upper end of the sleeve 89 a bore into which extends a rod 91. This rod 91 encloses with a lug portion disposed at the upper en thereof the crossbar 21 of the frame parts 83 of the backrest. This frame 83 is connected via a hinged connection 17 with the frame 10. The rod 91 com prises cross or transverse bores at different heights, and a holding pin 92 engages thereinto, securing the relative position between the rod 91 and the sleeve 89. The elastic force remaining the same, it becomes possible with the aid of this displaceable rod 91 to adapt the length of the spring means to a height adjustment of the axle 11 and therewith to a height adjustment of the seat. It may also be used, however, for varying the tension of the spring 90 and for adapting it to the weight of the user, the height of the seat support remaining the same.

While the preceding figures described above disclose embodiments which allow for a variation of the relative positions of the different parts of a seat system, the disclosure of FIG. 80 will now be described hereinafter. In this case, only one handle is used for locking different parts of the seat system. The axle 11 is secured to the base and pivotally supports the frame which represents the supporting element for the seat plate 10' and hence for the seat support. The backrest is secured to the frame 10 by means of a hinged connection 17. The backrest consists of upwardly open bent or formed frame portions 83 and a frame 84 which is introduced thereinto. Disposed at the latter by means of a joint 20 is a backrest leaf 85. The bent or formed frame portions 83 are connected with a crossbar 21. Attached to this crossbar is a telescopic spring means. or telescopic shock absorber means, which is secured with its lower end to the rod 16 of the base. In contrast to the preceding figures, this spring arrangement comprises a second sleeve 88' into which extends the rod 91. A clamp 95 which is adapted to act upon the sleeve 88 thus fixing the relative position between the sleeves 88' and 89 is disposed at the sleeve 89. This clamp may be rendered operative or inoperative by means of an eccentric mechanism which acts in the longitudinal direction of a clamping bolt 96; i.e. at right angle to the plane of the drawing. The handle or means acting on the eccentric mechanism is here shown to be a lever 97. A hand wheel may also be used instead. Rigidly secured to the sleeve or bearing of the frame 10 enclosing the axle 11 is a lever and a butt strap 101 is hingedly connected to the free end thereof. The strap comprises a slot which is identified with reference numeral 101' and through which extends the clamp ing bolt 96 including a pressure plate 96' When the bolt is tightened, also the butt strap 101 is secured in position in addition to the actuation of the clamp 95, the frame 10 thus being fixed in its relative position. In an analogous manner, a butt strap 102 comprising a slot 102' is connected to the hinged connection 17 and a butt strap 103 with a slot 103 is connected to the frame 84. The former serves for supporting the action of the butt strap 101 and effects a division of the load to be absorbed thereby. The butt strap 103 holds the backrest leaf at the desired height. All the butt straps are in contact with the one clamping bolt and may be secured in the respective position by means of the latter with the aid of only one handle or means 97. Further possibilities of movement of the seat may be determined, if desired. Reference is made in this context, for example, to the movement of the backrest leaf 85 relative to the frame 84, and to the adjustment relative to the depth of the seat support, as described hereinabove. For the sake of clarity, the butt straps necessary therefore have not been shown here but only indicated by arrows L. The frame 84 may be provided with transverse slots which, together with pins, allow for the setting of the basic height of the backrest leaf.

Instead of one handle or actuating means, two such means, as shown in dotted lines, or more may be provided. In the case of two such means, it is possible to either subdivide the butt straps into different groups, in which case one clamping means is coordinated to each group, or to extend the clamping bolt 96 beyond the pressure plate 96' and to attach a handle also at that end. This has the advantage that the seat may be locked from both sides, which is favorabie particularly for wheel chairs.

In order to guarantee at all times a perfect locking action, it may be advantageous to allow for the actuation of the handle or lever from the locking position only against the action of a spring Such a spring 97' thus supports the locking movement of the handle or lever 97.

A different method for the horizontal displacement of the seat support is illustrated in FIG, 8b. The frame 10 of the seat is positioned in sliding sleeves or bearings 104. These sleeves are rotatably positioned at the base by means of the axle 11, only a part of the tubes 12 being shown in this figure. The sleeves 104 are interconnected by means of a sleeve enclosing the axle 11. Rigidly attached to this sleeve is the lever 100. The seat support 10' is rigidly mounted on the frame 10. The respective position of the seat support with regard to the base may be fixed by means of the butt strap 102. The remaining parts of the seat system are the same as shown in FIG. 80 so that they need not be illustrated again.

When a seat system of the type described herein is installed, for example, in a construction machine or in a motor vehicle, it must be adapted to change its relative position to the ground-viewed in the sitting direction-only by a maximum of about 30 centimeters. It may in this case be suitable to support the telescopic shock absorber means on the ground rather than at the base. Such a seat is schematically shown in FIG. 9. A base is displaceably positioned on the ground by means of slide rails 120 and carries the pivot axle 11 for the supporting element 121 of the seat support. Mounted to the element 121 by way of a hinged connection 17 is the frame 122 of the backrest which carries via a joint 20 a backrest leaf 125 serving as carrier for the backrest upholstery as indicated. The frame 122 comprises a crossbar 21 on which engages a telescopic shock absorber means 123. This shock absorber means is supported against the ground and guided there in a slide 129. In order to keep the supporting point stable, a butt strap 128 is connected at the base 120 and engages with the other end thereof at the spring means, but may be detached therefrom When this connection is released or disengaged, the base or support of the spring means can be made to glide forwardly under the seat support. In this case, the backrest is set as extension of the seat support so that a reclining seat will result which rests with the rear end thereof on a support (not shown). The arrangement of the other butt straps and of the handle or lever corresponds to the foregoing description and is here indicated only by dotted lines.

The requirements with regard to stability are particularly great for seat systems used in this manner. In order to assure an additional safety, the butt straps 101, 102 may further be provided with a toothed system, as shown for the butt strap 201 in FIG. 10. A locking member 130 which is provided with an analogous tooth construction in as steep a fashion as possible is displaceably positioned on another but strap 203 intersecting at an angle of possibly 90, or on a corresponding guide rail being secured to the telescopic means. This locking member includes a guide bolt I32 engaging in the slot of a disc 133 being coupled with the handle or lever. The slot consists of a spiral with attached circular arc. When the locking connection is released, the locking member 130 is lifted out of the tooth construction of the butt strap 201 and releases the latter likewise for he longitudinal displacement. During locking, the spring 97' guides the handle or lever 97 and thus the disc 133 into a position such that the serrations of butt strap and locking member already engage mutually. The greatest portion of the spiral-shaped slot is thereby traversed. During the retightening by hand, the bolt 132 then engages in the circular arc-shaped part of the slot and thus renders it possible that, with the pressure of the teeth within each other remaining the same, the lateral clamping of the butt straps by means of the clamping bolt 96 is accomplished.

In all of the embodiments described above, the backrest is accommodated by means of a hinged connection at the supporting element for the seat support. The concepts of the invention may also be used, however, for set systems in which the supporting element and the backrest are rigidly connected with each other. An example for such a construction is shown in FIG. ll. In this figure, the pivot axle I1 is again guided, by means of lateral projections 80, in sleeves 81 being secured to the base and is adjustable with respect to its height with the aid of pins 82. The frame 10 is in operative engagement with the base by way of two chains 42, 43 which delimit the possibilities of movement thereof. For a height displacement, the chains are hung correspondingly longer. The frame 83 of the backrest is rigidly attached to the frame 10. Inserted in the open ends thereof is the frame 84 to which the backrest leaf 85 is mounted via a joint A spring means is disposed between the crossbar 21 of the frame 83 and the rod 16 of the base; it has been shown to be pivoted out toward the right for the sake of greater clarity of illustration. It consists of sleeveshaped elements 88', 89 which are supported against each other by means of a spring 90. The sleeve 89 comprises at the upper end thereof a bore through which extends a rod 91 into the sleeve 88'. This rod encloses with an eye or lug portion the crossbar 21. The rod 9] further comprises cross bores at different heights into which meshes a supporting or retaining pin 92, fixing the relative position between the rod 91 and the sleeve 89. The lower end of the spring means is supported at the rod l6 of the base. With the aid of the displaceable rod 91 it is possible to vary the tension of the spring and to adapt it to the weight of the user, the height of the axle ll and hence of the seat support remaining the same. It also serves, however, for coordinating the length of the spring means to the height adjustment of the seat support. The seat support 10' is displaceably positioned on the frame 10 so that the location of the weight of the user may be shifted either forwardly or rearwardly by a certain value, which has the efi'ect of a fine adjustment of the tension of the spring 90. Instead of the means shown, different means may also be used for varying the elastic force. Reference is made in this connection to a worm gear, for example, or to a toothed rack with locking mechanism, or an over sleeve with locking pin. As indicated in dotted lines, a support U0 may be positioned ahead of the seat support. It serves with the upholstered surface thereof for additionally supporting the thighs of the user, which may be of advantage for instance for handicapped persons. The support is slidingly positioned at the frame 10. The linkage "5 thereof is provided with a lockable joint "6 which allows for varying the support additionally also in the height thereof. Locking of the support with respect to the frame 10 is accomplished by means of a butt strap 114 which encloses with the slot thereof the bolt 96 in the same manner as the butt straps 111, 112 and 113 serving for locking the seat support as well as of the back rest with regard to height and angle of incidence. All of the butt straps are locked by means of the common handle or lever 97 whose action has already been described hereinabove.

in order to additionally secure the angular position of the butt straps with respect to the longitudinal axis of the telescopic spring means, toothed rosettes may be present, as shown as detail in FIG. 12. A rosette having a spur gearing or radial serrations is secured to the clamp 95 in such a manner that it encloses the clamping bolt 96. The counter rosette 14] being equally provided with a spur gearing is displaceably positioned on the bolt 96. It includes a recess in which is guided the butt strap 101 to be fixed. A compression spring 142 is added between the two rosettes. When the lever 97 is actuated for purposes of locking, the butt strap is moved toward the clamp 95 in the direction of the bolt. The toothed rosettes intermesh with respect to each other and fix the angle of incidence of the butt strap relative to the telescopic shock absorber means. The spring 142 serves for the purpose of separating the rosettes from each other when the clamping connection is opened.

It should be understood, of course, that the foregoing disclosure relates to only preferred embodiments of the invention, that interchanges of the elements and features described in the several figures of drawings may he obviously resorted to and that various modifications are contemplated without departing from the spirit and scope of the invention as hereinafter defined in the appended claims.

We claim:

1. A seat system such as for school children to enforce a good sitting posture comprising a seat member;

a backrest member;

a base;

a spring means;

means connecting said backrest with said seat member;

said spring means mounted to engage said backrest at the point of connection spaced from the point of contact between said seat member with said backrest;

means to move said seat member and said backrest relative to each other independently from each other;

said spring member connected with said base to provide a bearing force for the said seat and a forwardly directed stabilizing pressure upon the said backrest, when the seat is occupied;

means to limit the movements of said seat member;

means to adjust the spring tension of said spring means to the weight of the user;

means to lock at least one point of support of said spring means at varying positions;

means to lock the seat in varying positions;

means to lock the backrest in varying positions;

means to displace the seat member in a horizontal direction;

means to displace the seat member in the vertical direction; a depository means laterally secured to the said seat member exposed for use independently of the respective angle of incidence of said seat member; and

means to enable the occupier of the seat to maintain his back at all times in contact with the said backrest, independently of the position of said seat member, whereby an improper sitting posture will cause discomfort to the sitter and force him to adopt a correct sitting position.

2. A seat system comprising a backrest member;

a seat member;

a base;

a horizontal axis mounted in said base;

means to pivot said seat member forwardly and rearwardly abut said axis;

means connecting said backrest with said seat member; at

least one spring means;

said spring means mounted to engage the said backrest at a point of connection spaced from the point of contact between said seat member and said backrest;

said means to pivot and said spring means arranged to move said seat member and said backrest relative to each other; said backrest being connected with said base by said spring means;

said means connecting said base with said seat member in such a manner that, when a load acts upon said seat member, said spring means simultaneously produces a stabilizing forwardly directed compressive force on said backrest to adapt it to the position of the user and a bearing force against the said seat member.

3. Seat system according to claim 1, characterized in that said spring means includes a telescopic shock absorber arrangement.

4. Seat system according to claim 1, characterized in that said spring means comprises at least one flat spring.

5. Seat system according to claim 1, characterized in that means are provided for varying the height of said seat and further means for adapting the action of said spring means to the different heights of said seat.

6. Seat system according to claim 1, characterized in that disposed ahead of said seat is a support being displaceable with respect to height and/r depth of said seat, and in that means are provided for locking said support in different positions.

7. Seat system according to claim 2, characterized in that the portion of said backrest coming into contact with the back of the user is variable in the relative position thereof with respect to said seat, in that means are provided for locking the same in the various positions, and in that said locking means are adapted to be rendered operative and/or inoperative by means of a handle.

8. Seat system according to claim 2, characterized in that a pair of rosette-type cover members with lateral serrations is coordinated to at least one of said butt straps and in that said butt strap is guided in a recess of one of said rosettes.

9. Seat system according to claim 2, characterized in that at least one of the points of application of said spring means is displaceable when a corresponding locking means is disengaged.

10. A seat system as claimed in claim 1, said point of connection of said spring means with said backrest being spaced below said point of contact of said seat member with said backrest.

11. A seat system as claimed in claim 1, said point of connection of said spring means with said backrest being spaced above said point of contact of said seat member with said backrest.

12. A seat system as claimed in claim 1, said means to connect said backrest with said seat member being hinge means.

13. A seat system as claimed in claim I. said backrest member including an extension thereof with which said spring means engage.

l4. Seat system according to claim 1, characterized in that means are provided for locking said seat and/or said backrest in different positions.

15. Seat system according to claim 7, characterized in that said means are butt straps being provided with apertures 16. Seat system according to claim 15. characterized in that at least one of said butt straps additionally comprises a tooth construction into which a toothed locking member is adapted to engage.

17. Seat system according to claim 7, characterized in that at least two such means are simultaneously provided which are adapted to be rendered operative and inoperative by means of a common handle.

18. Seat system according to claim 9, characterized in that elastic means act upon said handle in such a manner that the locking means can be rendered inoperative only against the action of a spring force.

19. Seat system according to claim 7, characterized in that several of said means are simultaneously provide and are adapted to be rendered operative and inoperative by means of at least two handles preferably acting independently of each other.

20. Seat system according to claim 1, characterized in that said seat is positioned displaceably in the horizontal direction.

21. Seat system according to claim 13, characterized in that the supporting element for said seat is displaceably positioned. 

1. A seat system such as for school children to enforce a good sitting posture comprising a seat member; a backrest member; a base; a spring means; means connecting said backrest with said seat member; said spring means mounted to engage said backrest at the point of connection spaced from the point of contact between said seat member with said backrest; means to move said seat member and said backrest relative to each other independently from each other; said spring member connected with said base to provide a bearing force for the said seat and a forwardly directed stabilizing pressure upon the said backrest, when the seat is occupied; means to limit the movements of said seat member; means to adjust the spring tension of said spring means to the weight of the user; means to lock at least one point of support of said spring means at varying positions; means to lock the seat in varying positions; means to lock the backrest in varying positions; means to displace the seat member in a horizontal direction; means to displace the seat member in the vertical direction; a depository means laterally secured to the said seat member exposed for use independently of the respective angle of incidence of said seat member; and means to enable the occupier of the seat to maintain his back at all times in contact with the said backrest, independently of the position of said seat member, whereby an improper sitting posture will cause discomfort to the sitter and force him to adopt a correct sitting position.
 2. A seat system comprising a backrest member; a seat member; a base; a horizontal axis mounted in said base; means to pivot said seat member forwardly and rearwardly abut said axis; means connecting said backrest with said seat member; at least one spring means; said spring means mounted to engage the said backrest at a point of connection spaced from the point of contact between said seat member and said backrest; said means to pivot and said spring means arranged to move said seat member and said backrest relative to each other; said backrest being connected with said base by said spring means; said means connecting said base with said seat member in such a manner that, when a load acts upon said seat member, said spring means simultaneously produces a stabilizing forwardly directed compressive force on said backrest To adapt it to the position of the user and a bearing force against the said seat member.
 3. Seat system according to claim 1, characterized in that said spring means includes a telescopic shock absorber arrangement.
 4. Seat system according to claim 1, characterized in that said spring means comprises at least one flat spring.
 5. Seat system according to claim 1, characterized in that means are provided for varying the height of said seat and further means for adapting the action of said spring means to the different heights of said seat.
 6. Seat system according to claim 1, characterized in that disposed ahead of said seat is a support being displaceable with respect to height and/or depth of said seat, and in that means are provided for locking said support in different positions.
 7. Seat system according to claim 2, characterized in that the portion of said backrest coming into contact with the back of the user is variable in the relative position thereof with respect to said seat, in that means are provided for locking the same in the various positions, and in that said locking means are adapted to be rendered operative and/or inoperative by means of a handle.
 8. Seat system according to claim 2, characterized in that a pair of rosette-type cover members with lateral serrations is coordinated to at least one of said butt straps and in that said butt strap is guided in a recess of one of said rosettes.
 9. Seat system according to claim 2, characterized in that at least one of the points of application of said spring means is displaceable when a corresponding locking means is disengaged.
 10. A seat system as claimed in claim 1, said point of connection of said spring means with said backrest being spaced below said point of contact of said seat member with said backrest.
 11. A seat system as claimed in claim 1, said point of connection of said spring means with said backrest being spaced above said point of contact of said seat member with said backrest.
 12. A seat system as claimed in claim 1, said means to connect said backrest with said seat member being hinge means.
 13. A seat system as claimed in claim 1, said backrest member including an extension thereof with which said spring means engage.
 14. Seat system according to claim 1, characterized in that means are provided for locking said seat and/or said backrest in different positions.
 15. Seat system according to claim 7, characterized in that said means are butt straps being provided with apertures.
 16. Seat system according to claim 15, characterized in that at least one of said butt straps additionally comprises a tooth construction into which a toothed locking member is adapted to engage.
 17. Seat system according to claim 7, characterized in that at least two such means are simultaneously provided which are adapted to be rendered operative and inoperative by means of a common handle.
 18. Seat system according to claim 9, characterized in that elastic means act upon said handle in such a manner that the locking means can be rendered inoperative only against the action of a spring force.
 19. Seat system according to claim 7, characterized in that several of said means are simultaneously provide and are adapted to be rendered operative and inoperative by means of at least two handles preferably acting independently of each other.
 20. Seat system according to claim 1, characterized in that said seat is positioned displaceably in the horizontal direction.
 21. Seat system according to claim 13, characterized in that the supporting element for said seat is displaceably positioned. 